This invention relates to a method and means for stimulating the production of wells by fracturing the wellbore at a predetermined location.
The advantages of a horizontal fracture in an oil or gas-bearing reservoir have been pointed out by various authors. This is especially true for low permeability formations. For example, in a paper, SPE3010, entitled "Low Permeability Gas Reservoir Production Using Large Hydraulic Fractures," by Holditch, et al. presented by the 45th annual fall meeting of this society of Petroleum Engineers of AIME, in 1970, it was shown that in a formation such as the "Pictured Clips" (0.02md) having a formation pressure of 800 psi and a fracture capacity of 3md-ft, the productivity of 100 foot horizontal fracture would be approxmately six times greater than the productivity from a single thousand foot vertical fracture. Another example was analyzed and presented in a paper by Howard et al., entitled Hydraulic Fracturing, Volume 2, Henry L. Doherty Memorial Fund of AIME, Society of Petroleum Engineers of AIME, N.T. and Dallas (1970). It was shown for a much higher permeability formation (0.2md) with an extended pressure of 1700 psi and a fracture capacity of 150 md-ft showed that a 200 foot horizontal fracture was approximately 11/2 times more productive than a 200 foot vertical fracture.